Tiny biotech stock Achillion Pharmaceuticals (NASDAQ: ACHN ) reported what could be pretty big news for hepatitis C patients this week. The clinical stage biotechnology company released data showing that combining its ACH-3102 with Gilead Sciences' (NASDAQ: GILD ) Sovaldi achieved 100% cure rates in as little as six weeks of treatment. The success of that combination is prompting Achillion to launch a study of the two drugs over an even shorter 4-week dosing period. If that study pans out, it could be the biggest advance in hepatitis C treatment since Sovaldi won approval in 2013.